Wire Gauge

[Aussiemike]

So for one system this would be OK?
33 Amp?

solar diagram2.jpg

[Aussiemike]

And this for my separate 12v system?

solar diagram3.jpg

[littleharbor]

Yes, if the panels are 200 watts each.
Not exactly sure what you are asking.24 volt (panels)? If you are asking about the 250 watt panels and they are in fact 60 cell panels you definitely need MPPT and series wiring.
Yes you can use them with another MPPT controller and series, or parallel wire them for a 12 volt system.

[littleharbor]

So for one system this would be OK?
33 Amp?
solar diagram2.jpg

Series wire ALL 12 volt panels to get voltage high enough for the MPPT to do its thing.
Still need to move either + or - load and charging connections on the battery to lower string to help with even charging.

[Aussiemike]

Absolutey clear. I put my 12v batteries in parallel giving me 12v and the 250 w panels in series through an mppt controller.
Is the second diagram correct?

[littleharbor]

And this for my separate 12v system?
solar diagram3.jpg

You'd be better off using 6 volt deep cycle batteries if you haven't already bought them. If you haven't bought ANY batteries then 6 volt for both banks.

[Mike90250]

Slow down, and stop buying stuff. As you found out, you are spending money needlessly .

1) to charge batteries, you need higher voltage than the battery, to charge a 12V battery, you need up to 16V on the terminals. If you are using a MPPT controller, understand that they are very efficient at converting higher voltage to battery charging voltage, and for a 24V battery, you need panels wired so that their Vmp added up, is higher than 32V, up to 70V (or the controller limits)

2) wire batteries on the diagonal, per this example http://www.smartgauge.co.uk/batt_con.html

3) Sunking had some very nice schematics, I wish he was here to post them, showing fuses and such.

[Aussiemike]

Unfortunately I already have what I have.
Therefore is this diagram correct?
I really appreciate what I have learned here and have taken on everything said.
However, learning and understanding are two different things.
By putting up these diagrams I have really understood.
Do I need fuses here?
TIA Mike
solar diagram3.jpg

[Mike90250]

Yes you need fuses. At least 1 preferably 2, and some really picky folks, would say 3

Mandatory Fuse. At the + battery terminal. When you decide what your loads are, and what size wire. https://lugsdirect.com/WireCurrentAm...ble-301-16.htm
then you use a fuse that will blow before the wire melts.

I like to suggest the Blue Seas MRBF dual fuse, https://www.bluesea.com/products/215...k_-_30_to_300A
you can use 1 100A fuse for your Load cable, and another 40A fuse for your 40A controller

The 3rd fuse, goes between the charge controller & PV panels. If your panels have 10ga wire, use a 20A fuse, or the size listed on the sticker on the rear of the panels

I like to use DC, switch rated, Circuit breakers, because they are so much more handy

[Aussiemike]

Series wire ALL 12 volt panels to get voltage high enough for the MPPT to do its thing.
Still need to move either + or - load and charging connections on the battery to lower string to help with even charging.

Are you saying I should have ALL the 12v batteries in series. ie 48v????

[Aussiemike]

Sorry meant panels!!!!!

[Aussiemike]

Is this closer to the real thing.
Q. What is the amperage from the panels in this scenerio?
Q. Fuse 2 and 3?


solar diagram2.jpg

[Aussiemike]

Are these ok to go ahead and buy?

https://www.ebay.co.uk/itm/20A-DC-Circuit-Breaker-MCB-Solar-Fuse-125v-Single-Pole-1P-Ebike-TOB1Z-63-C20/272265686326?epid=2098500260&hash=item3f644cad36:g:L0YAAOSwbYZXc2eG

[littleharbor]

Those circuit breakers appear to be fine for DC usage. I don't see whether they're switch rated, if in doubt you should look into midnite solar DC breakers. Where, in your plan do you plan to use them? It's always nice to have a breaker panel with a circuit from panels to controller and controller to batteries. Note you wouldn't need a 100 amp breaker between a 40 amp controller and the batteries. As Mike 90250 mentioned you will need to fuse your loads, at oras near to the battery as possible. If you have an inverter going in the system it should have fuse rating in the manual.
As to the panel wiring, yes that's correct. The current from the string of panels is whatever the individual panels put out ,I'm guessing about 11.5 amps, so a 15 amp breaker would be fine.

[Aussiemike]

I am not sure where to put anything and am open to all suggestions. Unfortunately I do not have access here in Kenya to all you suggest so have to do with what I can get. If you tell me what size CB,s I need I will buy them. Thanks Mr. Little Harbour.